The endocannabinoid anandamide (arachidonyl ethanolamide) is the principal member of a family of regulators that are involved in modulating a number of biological actions including analgesia and specific aspects of the inflammatory response. It has been suggested that acid congeners of anandamide could exist as endogenous substances. This hypothesis was realized in a study that showed that such a substance, N-arachidonylglycine (NAGly), is indeed an endogenous constituent of many tissues and occurs at levels higher than anandamide. An interesting property of NAGly is its potent inhibitory effect on FAAH, the enzyme primarily responsible for the termination of anandamide action. FAAH is a serine hydrolase whose crystal structure was recently published, thus, opening the way for the rational study of the structural features of NAGly that confer its inhibitory properties. It has been reported that NAGly treatment in both in vitro and in vivo models, leads to a robust increase in anandamide concentrations. We therefore hypothesize that this inhibitory action is the basis for the anti-inflammatory action of NAGly and possibly other actions, e.g. analgesia. A major goal of this project is to synthesize a series of NAGly analogs as probes; these will be based on computer assisted docking analysis using the crystal structure of FAAH. The analogs will be tested in vitro as inhibitors of FAAH and compared with their effects on mediators of inflammation. The structure-activity data that will emerge from these studies will either support or refute the hypothesis. Anandamide appears to be involved in a wide range of regulatory functions through out the animal kingdom. Some examples are: the control of sensorimotor and motivational aspects of behavior, the regulation of implantation, hypotensive and bradycardic effects, cognition and drug dependence, the control of human pregnancy, sleep- wakefulness cycle, memory formation, locomotor activity, pain perception and modulation of the immune response. Thus, agents such as NAGly that can regulate in vivo anandamide levels could be effective modulators of many of these health related processes.